The present invention is related to seed drills and more particularly to such seed drills for planting seeds in a field of stubble without requiring a previous tillage operation.
"No till" farming has recently gained in popularity among conservationists and economically minded farmers as a solution to erosion, fuel consumption, irrigation, and fertilizer runoff. The "no till" concept simply removes the step of tilling the stubble from a previous crop prior to planting the next successive crop. Instead, the next crop is planted directly in the stubble. The stubble is very effective in holding moisture within the soil regardless of terrain conditions. This moisture-holding characteristic also serves to hold beneficial fertilizer in place rather than allowing it to run off with excess water to pollute nearby water sources. Stubble slows wind movement adjacent to the ground surface and therefore reduces evaporation and insulates the ground against chill. Seed placed evenly at an optimum depth on firm soil and covered by a loose high humus soil requires less moisture to start growth. Further, the insulation quality of the stubble is conductive to early plant emergence and adds protection against winter damage.
The "no till" farming method is further beneficial in that labor is saved through fewer required operations. Fuel is also saved. The "no till" operation can be effectively introduced once a field has been cleaned of undesirable weeds. This may be done with an appropriate herbicide. The herbicide is utilized to a prescribed soil depth with the new seeds being planted below that level.
The soil in a stubble field is ordinarily very hard and difficult to penetrate. For this reason, a seed drill must produce a substantial downward force against the drills in order to effectively penetrate the ground to a desired depth. For this reason, it has become desirable to produce a seed drill that will effectively penetrate such hardened ground and control the penetration in accordance to the terrain being planted.
In addition, with the increasing cost of seed, it is becoming increasingly desirable to utilize efficient seed planting equipment. Often seed drills include a form of metering device wherein spaced groups of seeds are allowed to fall from a seed dispensing chute to furrows formed in the ground. Although this procedure is serviceable, the individual seeds of each group are located too closely to one another within the furrow to enable proper growth of each individual seed.
U.S. Pat. No. 530,962 to F. R. Packham discloses a seeding machine utilizing a pair of converging discs with a seed dispensing tube disposed intermediate the diverging sides of the discs. In operation, the discs rotate in response to forward movement along the ground to form a "V" shaped furrow into which seed is dropped through the seed discharge tube. The discharge tube is located rearwardly of the point of convergence of the two discs in order to drop seeds directly into the open furrow. The discs therefore are utilized only to open a furrow and are not utilized for the purpose of spreading seed along the furrow.
The U.S. Pat. No. 1,104,725 to L. A. Aspinwall discloses a potato planter that utilizes an offset pair of angularly oriented discs for opening a furrow in the ground. Potatoes are planted directly behind the discs as the apparatus is moved along the ground. Again, these discs are not utilized to receive and space seed of any kind.
U.S. Pat. Nos. 3,762,480; 3,749,035; and 2,567,107 all disclose apparatus for adjusting the cutting depth or seed planting depth of a plow or drill. U.S. Pat. No. 3,749,035 to Cayton et al discloses in particular a hydraulic ram arrangement for utilization with independent seed planting and furrow opening mechanisms to provide precision planting depth of the seeds. The hydraulic actuators of this device are connected in a parallel hydraulic circuit and are connected to a sensing unit that automatically regulates pressure therein in response to soil hardness. The components are designed so pressure change in the fluid lines is of a required magnitude in order to maintain a constant furrow depth.
The "no till" seed drill of the present invention was designed specifically for "no till" type of farming and includes specific provisions to enable penetration of hardened stubble soil for fertilizing and seed planting. The present drill includes a heavy framework that mounts a plurality of pairs of discs. Each pair includes a forward coulter disc and a rearward furrow opening disc. The discs are angularly oriented so they converge to a point of tangential engagement forward of the axis of the disc. A seed dispensing chute or tube is located directly above the point of convergence in order that seeds may drop thereon to engage both discs and be held thereby before being moved rearwardly and subsequently dropped into the furrow formed by the two discs. The rotational action of the discs against one another serve to evenly spread the seed apart within the furrows. A hydraulic system is included and connected between the furrow opening discs and seed drill framework in order to provide a constant equal amount of substantial downward pressure between each pair of discs and the heavy framework as the apparatus is moved along. An annular flange is provided on each coulter disc to control the furrow depth.